Sen. Lindsey Graham was the latest prominent Republican to come out against Trump, saying today he cannot "in good conscience" support the billionaire.

It comes after House Speaker Paul Ryan said Thursday he's "not ready" to support Trump. Meantime, Mitt Romney and former Presidents George H.W. Bush and George W. Bush said they will also not endorse Trump.

John Roberts reported (video above) the latest from Omaha, where Trump will hold a rally later today. A protester got into brief spat with Trump supporters during the report, and was led away by security.

Meantime, Trump addressed the lack of unity behind his candidacy on Fox and Friends this morning.

Trump said that he, and many others, were very surprised to hear that Ryan would not commit to endorsing him.